Table 3.

Comparative Effects of Different Colon Cancer Risk Factors on Cumulative Incidence of Colon Cancer From Age 30 Years to Age 70 Years and Associated Relative Risks of Colon Cancer Obtained Using a Model Based on the Nurses’ Health Study, 1980–2004^a

Risk Factor	Cumulative Incidence (×10−5)	Relative Risk	95% Confidence Interval
PMH use
Never use	895	1.00
Current use (ages 50–70 years)	729	0.82	0.71, 0.93
Never use	895	1.00
Past use (ages 60–70 years; current use at ages 50–60 years)	830	0.93	0.82, 1.05
Height, inches
61 (155 cm; short)	797	1.00
67 (170 cm; tall)	975	1.22	1.04, 1.44
Body mass indexb
Average womanc	919	1.00
Consistently leand	850	0.93	0.87, 0.99
Consistently high body weighte	1,548	1.68	1.39, 2.03
Family history of colon cancer
No	895	1.00
Yes	1,384	1.55	1.29, 1.85
Processed meat or red meat consumption, servings/day
0	895	1.00
1	1,077	1.20	0.95, 1.52
Folate intake, μg/day
150	950	1.00
600	795	0.84	0.68, 1.02
Physical activity, MET-hours/week
2	1,359	1.00
21	681	0.50	0.32, 0.77
Cigarette smoking
Nonsmoker	895	1.00
10 pack-years before age 30 years	1,040	1.16	1.04, 1.30
Aspirin use
Never use	895	1.00
7 tablets/week	703	0.79	0.69, 0.89
Screening for colon cancerf
Never screened	895	1.00
Screened from age 50 years to age 60 years	816	0.91	0.86, 0.96
Combination of risk factorsg
Low riskh	622	1.00
Moderate riski	895	1.44	1.05, 1.96
High riskj	2,388	3.84	1.61, 9.16

Abbreviations: MET, metabolic equivalent; PMH, postmenopausal hormone.

^aUnless otherwise specified, all women were assumed to have no PMH use, no family history of colon or rectal cancer, average height, no pack-years of smoking before age 30 years, no aspirin use, no red meat or processed meat consumption, folate intake of 300 μg/day, and physical activity of 13.5 MET-hours/week, and to have never been screened for colon cancer.

^bWeight (kg)/height (m)².

^cAverage woman—weight: at age 18 years, 123 pounds (56 kg); at age 50 years, 142 pounds (65 kg); at age 60 years, 146 pounds (66 kg); at age 70 years, 145 pounds (66 kg). Height: 64 inches (163 cm).

^dConsistently lean—weight: at age 18 years, 105 pounds (48 kg); at age 50 years, 118 pounds (54 kg); at age 60 years, 120 pounds (55 kg); at age 70 years, 118 pounds (54 kg). Height: 64 inches (163 cm).

^eConsistently high relative body weight—weight: at age 18 years, 150 pounds (68 kg); at age 50 years, 185 pounds (84 kg); at age 60 years, 190 pounds (86 kg); at age 70 years, 185 pounds (84 kg). Height: 64 inches (163 cm).

^fScreening by either sigmoidoscopy or colonoscopy.

^gFor all 3 types, we assumed no PMH use, no family history, average height, no screening, and no aspirin use.

^hNonsmoker, consistently lean, physical activity of 21 MET-hours/week, no red or processed meat consumption, never having been screened, and folate intake of 400 μg/day.

ⁱNonsmoker, average body mass index from age 18 years to age 70 years, physical activity of 13.5 MET-hours/week, no red or processed meat consumption, never having been screened, and folate intake of 300 μg/day.

^jSmoking of 10 pack-years before age 30 years, consistently high relative body weight, physical activity of 2 MET-hours/week, 1 serving of red or processed meat per day, never having been screened, and folate intake of 150 μg/day.